Biscardi D

Evaluation of the migration of mutagens/carcinogens from PET bottles into mineral water by Tradescantia/micronuclei test, Comet assay on leukocytes and GC/MS.

This study monitored the release of mutagenic/carcinogenic compounds into mineral water (natural and carbonated) from polyethylene terephthalate (PET) bottles, using a plant mutagenicity test which reveals micronuclei formation in Tradescantia pollen cells (Trad/MCN test), a DNA damage assay (Comet assay) on human leukocytes and gas chromatography/mass spectrometry (GC/MS) for the characterisation of migrants. The water samples were collected at a bottling plant and stored in PET bottles for a period ranging from 1 to 12 months. Every month some samples were randomly collected and lyophilised, the residual powders were extracted with organic solvents and then analysed by GC/MS and tested for DNA damage in human leukocytes, or reconstituted with distilled water to obtain concentrates for the exposure of Tradescantia inflorescences. Micronuclei increase in pollen was found only in natural mineral water stored for 2 months. DNA-damaging activity was found in many of the natural and carbonated water samples. Spring water was negative in the plant micronuclei test and the Comet assay, whereas distributed spring water showed DNA-damaging effects, suggesting a possible introduction of genotoxins through the distribution pipelines. GC/MS analysis showed the presence in mineral water of di(2-ethylhexyl)phthalate, a nongenotoxic hepatocarcinogenic plasticizer, after 9 months of storage in PET bottles.

Studies of migration of potentially genotoxic compounds into water stored in PET bottles

Coloured polyethylene terephthalate (PET) bottles for carbonated beverages were studied for potential migration of genotoxic compounds. A combined approach, using physicochemical methods and a bacterial short-term mutagenicity test (Ames test) was followed. Standard EEC and US FDA tests for total migration of non-volatile migrant compounds into distilled water were performed, together with modified tests, where freeze-drying instead of evaporation of water was used, in order to measure both volatile and non-volatile chemicals. Gas chromatography-mass spectrometry (GC-MS) analysis was performed on these residues. PET bottles filled with naturally carbonated mineral water were also used for long-term total organic carbon (TOC) and mutagenicity migration studies (up to 6 months storage). Total migration results for PET bottles were within the EEC and US FDA limits. The use of freeze-drying for the elimination of water enabled much higher total migration data (higher than the limits) to be revealed. Some potentially genotoxic compounds (acetaldehyde, dimethyl terephthalate, terephthalic acid) were identified in these migrant compounds by GC-MS analysis. The tests for TOC migration gave a maximum value after 2 wk storage and the mutagenicity tests on non-volatile migrant compounds gave always negative results.

Leaching of mutagens into mineral water from polyethyleneterephthalate bottles

Polyethyleneterephthalate (PET) was tested as a source of mutagen contamination from bottles used for beverage packaging. PET bottles were filled with mineral water and stored in daylight and in the dark for different periods of time. The water samples were concentrated and the concentrates (non-volatile compounds) tested for mutagenicity with the Ames test (static tests). Total organic carbon (TOC) leaching was determined concurrently. Leaching of mutagens was also studied using dynamic tests; shaking distilled water in PET bottles. New methods were also used to test the leaching potential of both volatile and non-volatile compounds: directly testing the mutagenicity in unconcentrated water stored in PET bottles and growing Salmonella strains directly in the plastic bottles. The results were positive only for the static test, which identified leaching of mutagens after 1 month of storage in PET bottles. This activity was higher after storage in daylight.

The occurrence of cytotoxic Aeromonas hydrophila strains in Italian mineral and thermal waters.

Bacteria of the genus Aeromonas are ubiquitous in aquatic environments, including mineral drinking and thermal waters. Motile species are related to different diseases, mostly gastrointestinal disorders. Criteria for Aeromonas pathogenicity in humans and animals are still unclear and neither is the relationship between production virulence and pathogenicity factors. In the present study, strains of Aeromonas hydrophila, from 61 samples of bottled mineral waters and 23 thermal Italian sources have been isolated and identified by biochemical tests, for toxicity and detection of the aerolysin gene by the Polymerase Chain Reaction (PCR). Six strains were isolated from the mineral waters and were found to be cytotoxic and in possession of the aerolysin gene. For the twelve strains isolated from thermal waters, seven were cytotoxic and eleven contained the aerolysin gene.

In vitro genotoxicity of dimethyl terephthalate

Dimethyl terephthalate (DMTP), the para configuration of dimethyl phthalate, is one of the basic monomers used in the synthesis of polyethylene terephthalate (PET) plastics. Human exposure to DMTP may primarily occur during the manufacture of PET fibers and films. The mutagenic potential of dimethyl terephthalate was evaluated using a battery of in vitro short-term tests: the Ames test; DNA single-strand break assays in CO60 cells and in primary rat hepatocytes; UDS in HeLa cells; chromosome aberration and micronucleus assays in human peripheral blood lymphocytes; selective DNA amplification in CO60 and in Syrian hamster embryo cells. The results of this battery of in vitro assays clearly show that DMTP is nongenotoxic. By contrast, other authors have found DMTP to be an in vivo clastogenic compound and suggested that the mechanisms involved in these in vivo effects seem to have nothing in common with genotoxicity and are still unknown.